Influence of lesion of the median raphe nucleus on motility and dopamine turnover.

Both the spontaneous locomotor activity and the locomotor activity stimulated by apomorphine are enhanced in raphe lesioned animals. The exploratory activity does not show clearcut differences. After unilateral microinjection of dopamine into dopaminergic areas intensity of rotation and dominance of direction are amplified in lesioned animals. Other regions fail to evoke asymmetric or enhanced motoric reactions. The sensitivity of the dopaminergic system of raphe lesioned animals is increased too against unspecific stimulation, but with less strong dominance of direction. The general enhancement of motor activity reflects the inhibitory influence of the serotonergic system. In parallel to the change of behavior we observed a moderate increase of dopamine content connected with an accelerated turnover in lesioned animals.